remove_if and vector

remove_if.cpp

// -*- compile-command: "clang++ -std=gnu++0x -stdlib=libc++ -o remove_if remove_if.cpp" -*-
#include <iostream>
#include <vector>

int main (int, char **) {
  std::vector<int> ints = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
  
  // won't remove
  for (auto &x : ints) {
    // The following doesn't change ints at all, even though it
    // hits one every element
    auto it = remove_if (ints . begin (),
                         ints . end (),
                         [](const int y) { return true; });
    std::cout << x << std::endl;
  }

  std::cout << ints . size () << " elements in ints" << std::endl;

  // will remove
  for (auto &x : ints) {
    auto it = remove_if (ints . begin (),
                         ints . end (),
                         [](const int y) { return true; });
    ints . resize (it - ints . begin ());
    // And yet this will happen ten times!
    std::cout << x << std::endl;
  }
  
  std::cout << ints . size () << " elements in ints" << std::endl;

  return 0;
}